钠离子对TiO_2薄膜结构及其光催化活性的影响

采用溶胶-凝胶浸渍提拉法在不同玻璃基板上制备TiO2薄膜,并通过降解浸渍在薄膜表面的甲基蓝来评价其光催化活性。利用X射线衍射(XRD)、X射线光电子能谱(XPS)和紫外-可见(UV-Vis)吸收光谱等研究了晶型、表面元素分析和光吸收性能。并采用平行电极法测定TiO2薄膜的光电流,研究了薄膜表面载流子的复合情况。结果表明,薄膜的催化性能主要与基板热扩散到薄膜中的Na+和晶相相关。Na+抑制锐钛矿相TiO2的形成,并且在一定条件下促进由锐钛矿向金红石相的转变。Na+的扩散对TiO2晶粒尺寸影响不大。重要的是,扩散至薄膜的Na+不仅影响TiO2薄膜的晶相转变,而且成为光生电子与空穴的复合中心,同时影响其光催化活性。     

TiO2薄膜的结构和光催化活性研究

薄膜型的TiO2光催化剂克服了悬浮型的许多缺点,具有广阔的应用前景.阐述TiO2的结构及其影响因素;评述了晶型、晶粒尺寸、结晶度和晶格缺陷、表面积和表面预处理、表面羟基、温度、薄膜厚度、基体、光源及光强等因素对TiO2薄膜光催化活性的影响;探讨了提高TiO2薄膜光催化活性的措施,包括掺杂、贵金属沉积、半导体复合、表面光敏化等.指出需进一步研究的问题:加强影响因素的综合研究,探索最佳的工艺条件和反应条件;进一步提高TiO2薄膜的光催化效率;将光源种类从紫外光扩展到可见光;将TiO2薄膜的光催化性能同其它性能结合起来研究.     

TiO2薄膜的LPCVD法制备、表征及光催化性能

采用简单易行的低压化学气相沉积法(LPCVD)在GaAs、Si和玻璃衬底上沉积了TiO2薄膜,通过HRXRD、FESEM、EDS等手段对薄膜进行表征,结果表明基片对薄膜的晶相和微观形貌有明显的影响。薄膜的光催化实验结果显示,在可见光的照射下,分解甲基橙溶液时,砷化镓基和硅基TiO2薄膜表现出更强的光催化活性。并探讨了基片对薄膜晶相、微观形貌、光催化活性的影响。     

磁控溅射制备Cu2O和Cu2O/TiO2复合膜及其光催化活性

采用直流反应磁控溅射的方法在普通玻璃上沉积得到Cu2O、TiO2和Cu2O/TiO2复合薄膜.用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和X射线能谱仪(EDS)对薄膜的晶体结构、表面形态和薄膜元素组成进行了分析.XRD结果表明,当反应溅射时间为5 min时,Cu2O薄膜由单一的(111)晶面组成;反应时间的延长促进了Cu2O(110)和(220)晶面的生长.通过计算得出Cu2O(111)更有利于对O2的吸附.进一步使用氙灯作为光源,用薄膜对亚甲基蓝(MB)的降解率来表征光催化活性.结果表明,Cu2O/TiO2复合薄膜的光催化效果随着Cu2O含量的增加升高而后降低,当Cu2O含量为2.6mol%时,光催化活性最高.光催化效率的提高主要归因于Cu2O的加入引起光生电子-空穴的分离,而过量的Cu2O会延长光生电子迁移到Cu2O/TiO2界面和空穴迁移至表面所需要的时间,使电子和空穴复合的几率增大,从而降低了量子效率.     

纳米TiO2薄膜的制备及其光催化性能研究

采用溶胶-凝胶(Sol-gel)法在玻璃衬底上制备了纳米TiO2薄膜.采用X射线衍射仪(XRD)、紫外可见一光谱(UV/vis)和原子力显微镜(AFM)对纳米TiO2进行表征.结果表明,经300～700℃退火得到的TiO2粉体呈锐钛矿相,经800℃退火得到了锐钛矿相与金红石相的混合晶相,经900℃退火完全转化为金红石相.薄膜表面粒子分布均匀,表面平均粗糙度为1.54nm,该薄膜具有较高的光催化活性,可直接用于光催化降解有机物等领域,具有广阔的应用前景.     

Pb掺杂TiO2薄膜的制备及光催化活性研究

以硝酸铅和钛酸丁酯[Ti(OBt)4]为前驱体，用溶胶—凝胶法在活性炭表面制成了Pb掺杂TiO2薄膜，并用X射线衍射(XRD)、紫外可见光谱(UV—VIS)、透射电镜(TEM)对制得的Pb掺杂TiO2薄膜进行了表征，分别用甲基橙水溶液的光催化脱色反应、有机磷农药—氧化乐果(omethoate)水溶液的光催化降解反应评价了不同Pb掺杂TiO2薄膜的光催化活性。结果表明，薄膜为金红石和锐钛矿的混合晶相，相对于未掺杂的TiO2薄膜，由于金红石含量的增加，不同Pb掺杂TiO2薄膜的吸收带发生了微小的红移，Pb掺杂使薄膜的光催化活性明显提高，当Pb／TiO2质量分数为1．7％时，薄膜显示出最高的光催化活性。TiO2薄膜中的Pb可能以Pb(Ⅳ)和Pb(Ⅱ)两种形态存在，在紫外光的辐射下，Pb(Ⅳ)和Pb(Ⅱ)可能通过浅势俘获TiO2的光生电子和空穴而发生相互转化，减少了光生电子和空穴的简单复合，从而提高了薄膜的光催化活性。     

复合电沉积法制备Sn-TiO2纳米薄膜

采用复合电沉积法制备了TiO2质量分数为20.86%的Sn-TiO2纳米薄膜,研究了阴极电流密度、镀液温度、TiO2微粒的悬浮量等因素对薄膜中TiO2含量的影响,采用扫描电子显微镜(SEM)、X射线衍射(XRD)对热处理后的SnO2-TiO2复合薄膜进行了表征,以甲基橙为模型化合物对薄膜的光催化性能进行了测定.结果表明,在最佳工艺下所得复合纳米薄膜具有优异的光催化活性.     

A12O3／TiO2复合光催化薄膜的制备、表征及性能研究

近年来，二氧化钛光催化技术正成为光化学、能源、环境以及材料等领域的研究热点。作为一种新型的环境净化材料，TiO2光催化剂可广泛应用于污水处理、空气净化、抗菌除臭、表面防污、自清洁等方面，目前，TiO2光催化剂的固定化及其光催化活性的改善是TiO2光催化材料设计、开发和应用中急需解决的问题。本文利用阳极氧化和电沉积技术，在铝合金表面成功地制备出具有较好光催化活性的A12O2／TiO2复合薄膜。系统研究了复合薄膜的制备工艺；表征了复合薄膜的形貌、结构、成分以及光谱特性；详细分析了复合薄膜的光催化性能，并对这种特殊的复合薄膜形成机理进行了探讨。研究结果表明：电沉积液温度在薄膜制备过程中是最重要的影响因素，合理地控制沉积过程中的工艺参数可得到具有最佳表面质量和光催化性能的Al2O3／TiO2复合薄膜，H2SO4-Al2O3/TiO2复合薄膜经热处理，表面有锐钛矿结构TiO2生成，TiO2的晶粒尺寸在纳米量级；TiO2在加热过程中主要发生表面吸附水和吸附有机物的脱附、结晶水的失去及非晶相的晶化三种变化，且TiO2由无定形结构向锐钛矿晶体结构转变的温度为425℃左右；三种类型Al2O3／TiO2复合薄膜的表面形貌存在较大差异，这主要归因于三种铝阳极氧化膜的膜厚及表面微孔结构的不同；三种类型的复合薄膜均具有紫外光光催化活性；通过Fe离子掺杂改性以及萘酚蓝黑染料敏化处理后，复合薄膜的光催化性能可得到明显地改善；由薄膜形成机理的分析可知，TiO2主要通过交流电沉积过程中的阴极反应沉积于铝阳极氧化膜微孔处和表面上。     

HNO3处理对TiO2纳米薄膜的光催化活性和表面微结构的影响

通过sol-gel工艺分别在钠钙玻璃和预涂SiO2涂层的钠钙玻璃基体上制备了TiO2光催化纳米薄膜．然后用1mol／L HNO3水溶液对煅烧后的薄膜进行酸处理。用X射线光电子能谱(XPS)、扫描电镜(SEM)和紫外可见光谱(UV—VIS)对酸处理前后TiO2纳米薄膜进行了表征。用甲基橙水溶液的光催化脱色来评价TiO2薄膜的光催化活性。结果表明：SiO2涂层能有效阻止钠离子从玻璃基体向TiO2薄膜的扩散，普通玻璃表面的TiO2纳米薄膜经HNO3处理后，薄膜的光催化活性明显增强。这是由于TiO2纳米薄膜中的钠离子浓度降低以及表面羟基含量增加的缘故。     

衬底对溶胶凝胶法制备TiO2薄膜性能的影响

以钛酸丁酯为前驱体,经浸渍拉膜法在不锈钢以及表面预镀一层非晶态SiO2薄膜的不锈钢表面镀TiO2薄膜.利用XRD、FE-SEM研究了薄膜晶体结构与表面形貌,同时研究了不同衬底上薄膜光催化活性和亲水性,并与以玻璃为衬底的作比较.结果表明,衬底对TiO2薄膜表面形貌及性能的影响很大.以不锈钢为衬底的TiO2薄膜性能光催化活性较弱,但在表面预镀一层非晶态SiO2后TiO2薄膜的光催化活性有所改善.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from